The liquid development system employs a moving photosensitive surface which is uniformly charged electrically and subsequently is exposed to a pattern of electromagnetic energy, usually in the visible wavelength, reflected from an original document. There is thus formed on the photosensitive surface a latent electrostatic image. That image is then developed using a liquid developer having toner particles in a liquid carrier. The toner particles are attracted to the latent image under the influence of the electrical charge pattern, in combination with a development electrode. The developed image is thereafter transferred onto a copy medium. The photosensitive surface is then cleaned and prepared for its next use.
Various efforts have been made to improve the development process and the "completeness" of transfer to improve image density on the copy medium. These two process areas appear to be very important in obtaining high image density copies, especially when "bond" papers are employed. Generally speaking, bond paper has a relatively coarse surface, that is, relatively deep "holes" with a relatively small openings. Efforts have been made to improve the liquid development process in general, and in particular to improve the capability of liquid development with respect to "bond" paper.
The technological improvements have been directed for example to improving the liquid developer (see U.S. application Ser. No. 109,393, filed Jan. 3, 1980), the transfer process (see copending application Ser. No. 316,273, filed Oct. 29, 1981), and to improvements in the development station (see for example U.S. applications Ser. Nos. 282,223, 282,224, and 282,225, filed July 10, 1981). While these efforts have been successful to a limited extent, there still remains further "room for improvement".
It is therefore an object of the present invention to provide an improved method and apparatus at the development station of a liquid developer photocopying system for improving the density and resolution of the developed image and in particular the image copy quality provided by the apparatus. Other objects of the invention are a method and apparatus for use at the development station which are reliable, low in cost, and simple in construction. Another object of the invention is a method and apparatus which provide greater control over the many parameters, associated with the development station, which can affect machine operation and copy quality.